A conventional centrifugal liquid pump includes an impeller on a hub for pumping liquid from an inlet to the impeller to a pump outlet. Many such liquid centrifugal pumps experience the creation of vapor bubbles (cavitation) in the vicinity of the impeller hub. It has been observed that at low inlet pressures and flow rates this cavitation introduces discharge pressure variations and thus input power variations, sometimes called cavitation surges. In essence, the surge is caused by a core of vapor at the hub of the impeller, usually at the inlet area. The vapor is generated by the blade tips and collects at the hub due to centrifugal force acting on the more dense liquid.
This invention is directed to solving the above problems and suppressing cavitation surge in a centrifugal liquid pump.